The present invention relates generally to casting resins that are temperature-stable and color-stable. More specifically, the present invention relates to casting resins utilized for covering SMT-compatible optoelectronic components, such as optoelectronic multi-chip arrays.
U.S. Pat. No. 4,178,274 relates to transparent casting resins that are color-stable. They are preferably utilized for enveloping LEDs and SMT-compatible LEDs, which are referred to as TOPLEDs. These resins are only conditionally suitable for covering large-area components such as, for example, for covering the above-recited multi-chip arrays. Large-area coverings composed of the known resins exhibit cracks and adhesion problems that particularly occur after temperature shock treatment of after the soldering heat required for soldering. These problems can deteriorate the optical and/or electrical properties of the optoelectrical components.
Therefore, a need exists for an improved casting resin suitable for covering optoelectronic components that avoids the disadvantages of previous casting resins. The covering should be temperature-stable and color-stable to provide a longer service life. In particular, the molding material should withstand high continuous duty temperatures of 125.degree. C. as well as the temperature stress resulting from the soldering process.